Screen clearing mechanism for grain and seed sizing machines



June 15, 1948. w. J. PETERSON 2,443,543

SCREEN CLEARING MECHANISM FOR GRAIN AND SEED' SIZING MACHINES F11edApri1 11, 1945l 5 sheets-sheet 1 m Invem'o Hmmm J- Pe'rensom ATfoaNeYsJune 15, 1948. w. J. PETERSON 2,443,543

SCREEN CLEARING MECHANISM FOR GRAN AND SEED SIZING MACHINES Filed April11, 1945 5 sheets-sheet 2 l WILLIAM J. Pere-aso AT1-amava.

June 15, 1948. w. PETERSON SCREEN CLEARING MECHANISM FOR GRAIN ANI) SEEDSIZING MACHINES 5 Sheets-Sheet 3 Filed April 11, 1945 WlLuAm J. Pen-nsoJune 15, 1948. w. J. PETERSON SCREEN CLEARING MECHANISM FOR GRAIN ANDSEED SIZING MACHINES Filed Apil 11, 1945 5 Sheets-Sheet 4 WmmriLft-Temas June 15, 1948.

w. J. PETRsoN 2,443,543

SCREEN CLEARING MECHANISM FOR GRAIN AND SEED SIZINGMACHINES Filed April11, 1945 FMEA?,

5 shets-sheet 5 gmc/Www WxLLlAM J.' Pen-naam Patented June 15, 1948UNITED STATES PATIENT lf'oFFiczE i1 "This ."invention relates 4toimprovements 'in machines forsizing grains or seed; andparticiinlarlyfror."separating seed corn'i'nto anumber "ofclosely `anddoub'lydimensioned sizes to' facili- "'tate'its "planting,

" 'The' inventionhasfparticular' 'reference to" that 1 typl 'f's'chmachines "wherein a ".'plurality` of 'perforated sf':ree1"is"fare"assembled" insh'oes "and Vthe Whole vibrated both to travel"themateria1ovef'the screensandto cause' "the" material to f and'sepa'ratinglcontactWith 'the' 'openings'in'the screens. Asits rimaryobj ect myinventionaims `to generally improve 'such machines toA facilitate l and'improvetheir operation.

'An'other fandimportant objectis' to`z'proyide 'Vanimproved'lly"adjustable screen 'clearing 'or r cleaning 'l mechanism by' 'which the'screens' may be kept clear of all "lodgedV kernels "'ori particles andso" that the' 'machine mayoperate 'at all times at .fiill capacity.''This' has long beenaproblem A in thisiield, lsince Ythe"screens" inmaking *closely lsized -`sezvarations have a pronouncedv tendency 'toyclognip,l due to .thelldg'ement vof particles.' iri'the peningsg-/andunless this 'is yeffectively"counteracted it sapparent" that the--'fli'ciencyrof"'Ithe machine willffdiminish lrap'idly. In accordancewith my inventior'il'proifide a mechanism Where- 'in the undersides`if-"the'rxiachine -arec'ontinually wiped and'atthe same" timeupwardly'tapped 'or "struclibyWi-pe'rbars which are not only poweractuated ortraveledito lWipe andcontact allareas fc-Affthe screens; butare also .f power vibratedor A oseillated toeupwardly tapthe' screenandso dislcdgeany'lernels'br' particles from the openings. In connection'with' the'latter 'feature-vl of my invention, that ofiwer'oscillatingithe'*cleaning 4 bars," I also-embodyishockabsorption" meansof such-nature as tdprotect 'the'i-screens from -hard f blows and to`alloW""theWi1er bars to clear` kernels or particles falling'tli'rolighthe'wscre'ens Yand'so ,l prevent any injury to the seed `or grain.

y "These and other'moredetailed,andspeciflc obi :jects willbeiii'sclosgdinthecourseff 'the fin-110W- ing spec'iification,r'e'fere'ncebeing had'to thel accompayingidrawingsjinwhichfeig." 1 is e'sidemelevation'rof'my improved ma- -ciuine Z is a SimilarViW'butdookng'at'the-other sideff the macl'ne,

#Claims (Cl: 1209-1382) Figi 5 i-s-Lanienlarged?fragmentarydetailyiew'of one* *Wiper `elementiiardll lak-'part'. of 4Lits actuating*mecha-mism.

Figi-E6 fis :alve'rtical :longitudinal sectional View 5 `Athrong-h thevr'na'cil'iine but only fthe' uppermost screens bei-nglis-hown insection, 'fwhile the shoe carrying Ithe lower screen is fsh'own.inelevati'on Figi 7 isan-le'rlilargled fragmentary:sectional l0rsential-andifdrive'mechanismfor the wiper. struct1-1re.

Figi 8fis a det-ailf--secti-onalview alongi thelline -S in Fig. '7.

"Figv 9 veisean enlarged :fragmentary-.sectionalV'view''snbstarrtiazllyifalon'gthe liner-949 in'Fig. 6 k-but also-showing adj acent parts.. of the Wip ery :op-

'erating" mechanism.

A"`r'tef'er'ririgfrrovsr'more#particularly .and by refer- "ence-charactersto'fthe ldrawingg'my; machine asLshown-tlrerein'cormgirisesia main; frame cri frame- Workhavinguprightccirne `Vposts' I irigidly joined by cross bars N at upperdlowerendsiand ccnnectednti yupper er'rds -byl '-horfizontalzzupperiframe 'seen in -Fig.' 1,11the 'lowestends'cfv said'bars` being 'ilocated1 at" the delivery.endifoi'the' .machine -as a "Supporte'dhyland'Within'i-this framework areuppervand?lowerlsho'espdesignatedgenerally 'at l i and'fl 'fwhich "arearrangediin superimposed if'ffithel delivery endJc-fthamachine. Theshoes frame havingsidesfl', rigidly connected together as Will laterappear, and saidfsideshave suitable screens'f I lrfaiidSI-S aresupportedy Ionefabove the 401 ttlier.' lSince thespecicv screen mountingforms vrio-:part1ct"rnylpresenirinvention it is not rdetailedherein;-itfbeingfmerely noted that thezscreens Il and-"fl Slmay-be'-slippeden'dwise into.y the shoes betweenthesidessl thereof andfremovedtherefrom -1ifat= will. Fors thispurposethe' higher or feed ends -lffofythe'S'sho'esn-arel proVidedwi-th removable end "--pl'atesI I9 (Figf):aligned-With thef screens and "i vihicl'i.:mayfy bei removed vwhen e thea screens are ebein'g iclianged. Mother 'permanently mounted end plates23 securer the 'slloey sides i5 together at this'iend. t

"Forcorin :'gradingf"each-screenl I1-and It is '-Smader in two isections, onery section indicated at Ila and ISa for each screen havinga screen making width classifications of the corn, and the othersections, indicated at IIb-|81, having screen plates punched withelongated holes or slots 22 (Fig. 3) for making thickness classi--cations. Each screen section has a separate rectangular frame 23 towhich the perforated plates are fastened.

The screen arrangement and gathering kmeans for the variousclassications of the corn as here shown are largely conventional andwill accordingly be only briefly described. The round holed screensIlla-I3a are arranged to receive the corn first and the corn rejectedby'these screens is caused to travel down lengthwise over thecorresponding slotted screens IIb-ISI. A hopper 38 is provided as thefeed means for the upper screen. The corn rejected by the screens istaken off through delivery spouts 24, 25, 26 andV 21 respectively. Thethroughs from the uppermost screen I'Ie are carried back to the head endof the screen I3EL next below by a return pan 28 disposed below theuppermost screen and which slopes back in the direction of the feed endof the machine. In turn the throughs fromscreen I 8a are collected byanother return pan 29 and carried back to the head of the upper roundholed screen in the lower shoe I5 and the action is repeated thereinuntil the lower round holed screen is reached. The throughs from thisscreen are delivered in the usual manner from a laterally extendingtrough 39 (Fig 2) attached to the lower shoe. 1

The throughs from the slotted screens IIb- I8b in both shoes arecollected on bottom plates indicated generally at 39 and separatelydelivered from the ends of the shoes by spouts 3l, 32, 33 and 34. All ofthese end spouts are conveniently fastened, as indicated at 35, acrossthe ends of the shoes at proper levels to receive the various grades ofcorn, and serve also to tie the sides i6 of the shoes together.

As seen in Fig. 6 the throughs from the upper end portions of the upperthree slotted screens IIb-I8b may be collected by laterally dischargingtroughs 36 and delivered separately from the corn emerging from thespouts 3I `to 34. Thus the screens I lb-I 8b may, by using slots ofdifferent width at upper and lower end portions, each make threeseparate classifications. As a result, the four layer or four deckmachine here shown is seen to make no less than twelve sizeclassifications of the corn. I do not, however, limit the application ofmy present invention to this specific screen arrangement since it may bevaried according to the kind and class of grain or seed being sized.

To progress or travel the corn or seed over the screens and to cause itto bound about thereon as required for proper operation of the machine Iprovide means for shaking or vibrating the shoes I4 and I5 as will nowbe described.

The upper shoe I4 is supported for lengthwise swinging movements byflexible metal straps or hangers 49, one at each corner, and lower endsof these straps are secured at 4I to the shoe sides I6. The upper ends fthe straps are secured at 42 to the upper part of the main frame. Thelower shoe I is similarly supported at each corner by straps 43 securedat upper ends at 44 to its sides I6 and secured at lower ends at 45 tothe lower part of the frame. Thus the shoes may be vibrated or swunglengthwise independently of each other.

The shoes are thus operated, and the entire machine powered, by anysuitable prime mover or power source, such as an electric motor 45,belted as at 47 to a pulley 48 on a main drive shaft 49. Said driveshaft 49 is journaled in bearings 5I] supported on the corner posts I9at the feed end of the machine, and the motor is pivotally hung at 5I onthe frame to keep the belt 4'i' taut. f

The drive shaft 49 carries near each end a pair of eccentrics indicatedin Fig. 6 at 52-53 which reciprocate eccentric arms or pitmans 54-55adapted to be respectively connected to adjacent corners of the upperand lower shoes I4 and I5.'

' p As one way of connecting these parts I show the pitmans' 54-55 asconnected to flexible straps 56 and 51 which are in turn bolted as at 59to the shoes. The arrangement is obviously such that the rotation of thedrive shaft 49 and the eccentrics 52-53 thereon will swing the shoes I4and I5 back and forth through a limited range, and with the eccentricslocated oppositely as here shown with respect to the axis of the shaft49, the shoes will move in opposite directions. The speed of thismovement is such that a pronounced vibration of the screens and the seedor corn thereon results, and I have found that a rate of vibration of400 per minute, and a range of one-half inch gives good results for mostpurposes.

My present invention relates to the screen wip-- ing and clearingmechanism now to be described. For the four screen layer or four deckmachine herein shown I provide at each side thereof a carrier framecomprising four parallel and vertically spaced bearing or carrying bars59, Gil, 6I and 62 secured together rigidly by upright bars 63-54connecting their ends. The bars 59 through 52 are located parallel withand below the level of the respective screens I'I--I8 within the twoshoes I4 and I5 and, of course, slope vtoward the delivery rend of themachine. The grid-like rectangular frames thus formed at each side ofthe shoes, are supported for reciprocating movements lengthwise of theshoes and parallel with the screens b y two upright supporting bars orsupport members 65 and 65 at each side of the machine and which arespaced apart lengthwise thereof. Near upper ends these bars 65 and 66carry peripherally grooved pulleys or rollers 5l over which theuppermost bearing bars 59 ride and these pulleys are located at properand different levels so as to support and guide the carrier frame formovements in the desired sloping, longitudinal plane. As seen in Fig. 9the bars 59-62 are made from angle irons and to guide the frame on thepulleys 61 and hold it thereon short sections of rod 58 are weldedinside the angle of the upper bar (Fig. 2) to ride the grooves of thepulleys.

The manner in which the supportin-g bars E5 and 63 are themselvessupported will be described later.

Each of the bearing bars 59, 59, GI and 52 at each side of the shoescarries six, more or less, spaced bearings, designated throughout at 59,and in each aligned pair of said bearings on the opposite sides of theframe a wiper or rocker shaft 'I9 is journaled. There are, accordingly,twenty-four of the shafts 'I9 in the machine here shown and' they aresupported by the bearings transversely beneath the respective screensI'I-I8, with three of the shafts located beneath each round holed andeach slotted screen. To pass the shafts the sides I6 of the shoes I4 andI5 are provided with openings 1I and these openings are not onlyelongated in the direction of the ---lengtheofithe-` machine towperamt.the shaf ts f to move'backcand-frthf With-the carrier* framesibutaresofwdervrtiallyeas 'to per-mit ysubstaritaliup a-idfldown adjustmentsoff'- he: shaftslaswill-preswhich extern-'parallel' with the shafts`aud-i cross -H 'fWi-sewth respect-td thescreensf- Preferablyfthesefwwipeebarsd'- "M -are of-rubber or-other vresilient v material'ar'id'ft'hey arebf #such "length asl' to fsub fstantiaflly completely"Sloan the lscreens'crosswise *The entire carrier'frame1'inclu'clirigf"the wiper.;

shafts and bars fareipower travelled'to' 'cause the f-barsto 1wipeundersiozesof-"theTrame-iasI will now ing"brafcketli16crosswise of 'the'lower frame barst A crankshaft 86 is journal-edin'bearingi'brackets ilif' in--the lower -part of the f frame *parallel-"With Y.lightedfsprocketsfZ"arid-333 ""(Figf) ^over which isi trained asprocket chain 84. -Thearrar1ge ement-is such thatthe crankshaft isdriven by 'Y vthe-motor'156` but' at a relatively slowj speed. l A

meeting rodi 236i which extends lout --tothe f eed. end -=of-=themachine and is -upivota'llyconnected at" 8'! f -'-toithe lower end'cf acrankf'a'rni" 88. This-crank arm 88 is secured to a rockshaftfS-joumaled well below the drive -shaftfll in bearing brackets* 3Bsecured to the Vadjacent frame corner` posts WIB. -4:Said'sliaft 33:alsoizcarries: cr-rop'erates' upumwardly ri exteihding.Y crank. Alevers?9 iii al-ignedfwth the:ladjacent'vienda'bars it/'ofi 'thefswiper'carrier Y "frameiemdi-the: respective' crank armsfatteach-i` .asiden ofthe frame-areconnected to said-barsf f Abyff'lrik rods'e2. It Wil-l bereadily: apparentfthat the aforesaid, rotation of the'r` crankshaft 804will causefthefcrank"leversff l; to'-.osc`ill'ate iinupright:filongitueinal planesaa'ndj thisfimovement 4will tbe E'lpfb-einglguided therebyisothat "the wiper." bars* ffMrtravelfback-:andfortl'r'pathsparallel vwithutloe screens, atheamplitude of @this`movement',I or :v stroke, is isu'ch' '1 that"A the Lwper v 4barsiiwillr'fcoll'ectivelywiper or cover 'thefull -length o-the-:screensunder-surfaces. Thestroke' is. adjustable` by zthe? 1power'f'driven;.rcking'm'echanism-whichfwillf next lbe described'rAti'one'sside-i off fthe machine; ithat' viewedzin Fig 1 I'the "shaftsfextend' fllo'eyond '.1 their. bearingsfi f and are each.'.prfwid'edonfthis sfextended"endizwith' atfcollarf 5315 securedstofI the carriesspaced outwardly turned ears` Bfprovided v'mi'itheir.-'proximatefsurfacesitawitlr; L,bring l. lAso meuntdiionflthisfiend.foffieachfifshait l0 and-eouwadlya'of".thefzcbllars 84 fis: a crankrfcr'irockerzA arme@ 8:txrzhiclieEd'cpfendsL lostmotion;.counection-betweenthefrockerfcranks 15""ated;ihcleperrdenttfmovemorltsf of .thefshafts'finfop- :hesite'directionsY relative"toffsaidsfcranks. The purpose of theseresilient-fconnectionszendim- Vfrfportance thereof r'will presently Lbepointed out. i.The'.rocker'icranksa shave outwardlyaturned :pins:I-Mfon'ftheirflower'fends anclxthree adjacent .ivcranks off-each=layerf, :or-'those :operatingfthe l"wiping and. .clearing vxbars ,fofeachl screen el 1 -1i 8,

connected "by connectingffbars: ori beamswl B5 which may well'y be i of.oil f impregnated wood "and 25 f provided withbearinga.aperturesetoreceivewsaid 3Dialect-ed to.-thesefends take thei'form. off-bell cranks ,-aflongitud-inal movements. of. .ft-heconnecting-- bars ffthe'twee.vertical tiers of^-,rocker assembliesare UFindependently.- operatival by..'the r-barstHi8- HNL .-"thewlowerI yends7ofwhich depend below the lower eh-oe vfor operatingthereat...Jllhebarsel 33e-dill] Amay also be'- offzoil.impregnated'-fwood.

. 4rranges r-between fthe. pitman" barsT .le x2-1.39

45. .isi-an; inverted: Ueehapedebridge frame H il .having 'shoesfandwhi-cbhas a-topportion .CM2 eonnect- .f ing-these :sides frame lala.accordingly 3o-moves asa unitwwith the-.carrieriramelasothe ywipingaction` takes` rplace. The.. lower.rends, o ftherarneI sides F.i H l,depend below theflcwer.- .shoe

= shaft H 4 1f, is -journaled and.- 'suppor-teolf crosswise a5rbeneaththeshoe. his shaft M Lis. driven by .1f means-01"'` apulleyofononefendover which is trained a-beltH.leading..upxafardlyeauclxover f" hung. yfremmthe upper. frame. AAbarsl 2 supporting `:tlleslfiat- Irl 8 :crosswseof .the machine .and :aboveleeuppershoe. kr'lfheshaft.llalso carriesfan- ,otherf pulleyl-.andf a:belt fl 2 l .leads therefrom to afr-vpuilleyflgonvthewmain.countershaft l .leep.-,tl'1e belt .f :i i taut-.arid1 fcompehsate lforl .the travel o.- pulley l-i 5.l `with e respect to .pulley ll'clfasathe xFJvfip-erifra-mefmovesfbacklandaiorth, ll r-, provide aswmgablysupported ancle-spring-Y actu-- Tomated .tigl'itenerJ-pulle;r f-lZ-I!t(Fig. 2)."y inusual-manner.

bearings |25 in which are journaledoactuating jacent the lower ends ofthe rocker actuating pitman bars IUS-|09. Eccentrics |28 and |29 on theshaft I I4 (Figs. 1 and 8) are provided with oppositely directed arms|3|l|3| having bearings |32 at their ends for pivotally engaging pins|33 at the lower ends of cranks |34 secured to and depended from therespective shafts |25 and |21. The rotation of the shaft ||4 will thusbe seen to oscillate the shafts |26 and |21 and the ends thereof areprovided with cranks IE5-435 (Fig. 1) which are pivotally connected at|31 to the pitman bars IUB-IUB so that such oscillation of the shaftswill move these bars alternately up and down. As aforesaid this movementof bars IUS- |09 is translated to vibrating or rocking movements of thewiper bars 'i4 about the axes of the shafts 1|).

To keep the openings 1| in the shoes closed at all times during themovements of the wiper rocked shafts 16 I provide for each row of saidopenings, on each side of the machine, an elongated closure or stopstrip P38 wide and long enough to completely close said openings. Toaccommodate the shafts 15 the strips |38 are provided at appropriatepoints with exible retainers in the form of pieces |39 of rubber beltingor similar material held on the strips by turning their upper edges overupper edges of the pieces as indicated at |46. (Fig. 9 particularly.)Said rubber belting pieces |39 have centrally 'located apertures |4| topass the shafts 1|) and are split from these apertures downwardly asshown at |42 (Fig. 6) so that they may be spread apart to slip over theshafts. When properly positioned the strips |38 t against the sides I6of the shoes and they are held thereagainst by springs |43 secured tothe bearings 69 and turned inwardly and downwardly to bear against thestrips. Obviously then, the strips may be pulled upwardly and removedwhen required but when put in place they will slide back and forth alongthe sides of the shoe as the back and forth wiping action takes place.Behind or inside of the belting retainers or pieces |39 the strips are,of course, themselves cut away as at |44 (Fig. 6) to clear the shafts.The strips serve to prevent the escape of material from the openings 1|.

The carrier frame supporting bars 65 and (it are arranged for up anddown adjustments in the following manner. At upper ends the bars areslotted or notched at |45 to accommodate bolts |46 in arms |41 which arerigidly secured to and depended from the top of the main frame. It willbe noted (Figs. 3 and 6) that the bars 65 and 65 are channel-shaped incross section and the arms |41 are disposed in the channels to hold theparts against twisting out of alignment. At lower ends the bars are alsodownwardly notched at |48 to accommodate bolts |49 which are secured toflat link bars |50 and |5| and depend from the bars 65 and 66respectively. Disposed transversely beneath said bars are supportingshafts |52 and |53 journaled in bearings |54 secured to the lower framebars I3 and upon these shafts are rigidly secured supporting cranks|55|56 to the lower ends of which the link bars |56 and I5| arerespectively pivotally attached, as designated at |51. It will thus bereadily appreciated that, by oscillating the shafts |52'and |53, thecranks |55|56 may be moved in vertical planes to raise and lower thesupporting bars 65 and 66 and thus correspondingly adjust the entirecarrier frame and wiper structure bodily.

Adjacent one end the supporting shafts |52 and |53 are provided withupwardly turned levers |58 and |59 and to the lever nearest the deliveryend of the machine there is pivotally attached a link rod |66. To theother lever |56 there is pivotally pinned a strap |6| having one endturned and apertured to pass the end of the link rod |60 upon which isthreaded a nut |62 by which the effective length of the rod, and hencethe relative distance between upper ends of the levers |53 and |59, maybe adjusted. To the other end of the strap |6| there is pivoted anadjusting rod |523 which leads therefrom out through an aperturedbracket plate 64 secured to the adjacent corner post i6. This end of therod |63 is threaded and screwed thereon is a hand crank |55. Byturningthis crank the rod |53 may be lengthened or paid out to allow thesupporting shafts |52 and |53 to turn in a direction for bodily loweringthe wiper mechanism, while by oppositely turning the crank the shaftswill be turned to lift said mechanism. The weight of the mechanism will,of course, hold the crank against the plate |64.

At one side of the machine the link bars |50 and |5| are each turnedinwardly at upper ends |55 (Fig. 4) and immediately thereabove thesupporting bars 65 and 66 are provided' with tapped inwardly turned lugsB61 in which are threaded set screws |66. By turning these set screws|68 downwardly against the ends |66 it will be evident that thesupporting bars 65 and |56, and the entire wiper mechanism, may beraised and lowered at one side and with respect to the other.

Operation The general operation of the machine has been described and itwill be understood that the corn or other material will be caused totravel over the various screens as the shoes |4 and i5 are vibrated bythe eccentrics 52 and 53. ln such travel the particles have a pronouncedtendency to become lodged in the screen openings and to counteract thisthe wiper bars 14 are caused to move back and forth beneath the screensby the reciprocating travel of the wiper carrier frame including theframes at each side of the shoe. This reciprocating movement is causedby the crank lever 9| as has been described. At the same time the wiperbars lil are oscillated or rocked back and forth in longitudinalvertical planes causing them to intermittently upwardly tap theundersides of the screens and so upwardly dislodge any kernels orparticles from the screen openings. Thus by the combination of thewiping and tapping actions of the bars 14, both power driven, it will beevident that the screens can be kept clear at all times.

Turning now to more `specific but important features of my invention itwill be evident that the springs ||l| and |62 not only provide a shockabsorption effect such that wear on the wiper strips and screens isreduced but furthermore that the independence of movement of the shafts1E) and the wiper bars 14 with reference to the power actuated rockingmeans enable the bars to clear any falling kernels or particles whichmay be encountered. In other words, the wiper bars may clear any suchkernels without crushing or injuring the same, by virtue of thisresilient connection.

Inasmuch as the wipers must operate close to the screens for best effectthey must be lowered out of the way when the screens are being movedendwise for replacement and this may be readily accomplished by turningthe hand crank |65 to lower the entire wiper mechanism as a body. Alsoby adjustment of this crank the wipers may be raised or lowered to varytheir distance below the screens and so regulate the intensity withwhich they tap or hammer thereon. An adequate range of movementvertically is provided for these purposes by the width of the openings1| through which the shafts pass.

The entire wiper assembly may also be tilted lengthwise or in ahorizontal vertical plane with respect to the screens by adjusting thenut |62 to vary the relative angular positions of the su-pporting cranks|55 and |56. Thus the wipers may be adjusted to bear evenly on the fulllength of the screens, or to strike one end or the other with greaterintensity as may be required. Similarly the entire wiper mechanism maybe tilted laterally or in a transverse vertical plane with respect tothe screens by adjustment of the set screws |68 to raise or lower oneside. The wiper bars may thus be readily leveled as required to evenlycontact the full width of the screens.

It is understood that suitable modifications may be made in thestructure as disclosed, provided such modications come within the spiritand scope of the appended claims. Having now therefore fully illustratedand described my invention, what I claim to be new and desire to protectby Letters Patent is:

1. Screen clearing mechanism for the screen of a sizing machine,comprising in combination, a wiping device rockably supported beneaththe screen crosswise thereof and including a shaft and Wiper barsconnected thereto the latter being disposed transversely of thedirection of motion of the screen, power actuated means connected to theshaft to oscillate the same and rock the wiper bars alternately upwardtoward the screen, and power `actuated means for moving the wipingdevice bodily back and forth lengthwise with respect to the screen andin substantially continuous contact therewith.

2. In a material sizing machine of the character described including ascreen assembly, wiper mechanism for clearing the screens of lodgedparticles of material, comprising Wiper members positioned beneath thescreens, a frame assembly at each side of the screen assembly andsupporting the wipers, means for oscillating the wipers to cause them totap the undersides of the screens, rollers supported alongside thescreen assembly, the said frame assemblies being supported on saidrollers for reciprocating movements with respect to the screens, andmeans for moving the frame assemblies on the rollers to move the Wipersback and forth beneath the screens.

3. In a material sizing machine of the character described including ascreen assembly, Wiper mechanism for clearing the screens of lodgedparticles of material, comprising wiper members positioned beneath thescreens, a frame assembly at each side of the screen assembly andsupporting the wipers, means for oscillating the wipers to cause them totap the undersides of the screens, rollers sup-ported alongside thescreen assembly, the said frame assemblies being supported on saidrollers for reciprocating movements with respect to the screens, meansfor moving the frame assemblies on the rollers to move the wipers backand forth beneath the screens, and the said rollers being supported forindependent and simultaneous up and down adjustments with respect to thescreen assembly for adjusting the Wiper members with respect to thescreen.

4. In a material sizing machine of the character described including ascreen assembly, wiper mechanism for clearing the screens of lodgedparticles of material, comprising wiper members positioned beneath thescreens, a frame assembly positioned at each side of the screen assemblyand operatively supporting the Wipers, support members adjacent saidframe assemblies, rollers on said support members and engaging andsu-pporting the frame assemblies for reciprocating movements to carrytheY wipers back and forth beneath the screens, means for reciprocatingsaid frame assemblies, and means for both selectively and simultaneouslyvertically adjusting said support members to adjust the wipers withrespect to the screens in two angularly related planes.

WILLIAM J. PETERSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 142,023 Hunter et al. Aug. 19,1873 190,572 Fulton May 8, 1877 403,088 Burnap May 14, 1889 427,774Lister May 13, 1890 1,122,765 Kime Dec. 29, 1914 1,202,378 Fraser Oct.24, 1916 1,234,299 Dibert July 24, 1917 1,247,427 Liggett Nov. 20, 19171,286,389 Mullen Dec. 3, 1918 2,051,085 Ilseman Aug. 18, 1936

